Process for making wallboard



"Jan. 8, 1929. 9 1,698,351

' W. STOREY PROCESS FOR MAKING WALLBOAHD Filed April 20. 1926' Fig: 9 j Fig 5'.

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3 Ma 2W //V P7 2 7[ Z L L A I 9 I 7| F'J JT- 4 4 i 9 7 INVENTOR OZz'z/er W. Storey BY ATTORNEY5 Patented Jan. 8, 1929.

UNITED STATES PATENT, orrics.

01.1mm. w. greasy, or manrson, wrsoonsm, ASSIGNOR, BY MESNE ASSIGNMENTS,

'ro'c. IE. Business nanor'mromnsrne, or

or DELAWARE. r

DOVER, DELAWARE, A CORPORATION PROCESS-FOBHMAKING WALLBOARD.

Application filed April 20, 1926. Serial No. 103,393.

The. present invention relates to a process for making wallboards suitable for use on the walls or ceilings of a room and having good heat insulating qualities. It is made from a mixture of a filler and a binder'which pufi's into a porous rigid coherent mass under the action of heat and is provided with a facing of other material.

It is an object of the present invention .to produce a flat surface on an improved wallboard or other flat molded product composed for the most part of inorganic material,that product being light in weight,cheap in cost, and having a high porosity,and, consequently. a low thermal conductivity. The wallboards of the present invention may be of the thickness and of the sizeof ordinary paper wallboards, and have a faclng of paper, cloth, or other facing material on one or both sides.

As set forth in \Veiss and Norris application Serial No. 720,511, filed June 17, 1924, (now Pat. No. 1,628,206, granted May 10th, 1927) when an intumescent binder such as a soluble alkali silicate, hide glue or cornstarch is mixed with a filler and subjected to the action of heat, the mass expands or puffs up and ultimately hardens into a firm strong body filled with air cells or pores. In Serial No. 720,510, filed June 17, 1924, Weiss and Norris disclose a method b which the mixture of alkali silicate and ller may be used in the manufacture of wallboards. About one part alkali silicate, such as sodiumsil cate, having a density of about 425 B. is intimately mixed, as in a mixer, with about two parts of a tiller such as pulverized limestone, which may be dolomitic in character, to a dougl'ilike consistency. A soap, or a fatty acid,.such as oleic acid, which forms a soap with the soda in the sodium sihcate, may be added in small amounts to ald in securing a better puffing action. \Vhen the board or panel is to have a paper facing on both sides, the dough or mix thus formed is spread upon a sheet of paper either in an even layeror as stripes, (an even layer having a depth of 7 3 to A, will form a boar-dapproximately {3 in thickness). A second sheetof paper is placed on top of the dough so that the product in its green condition consists of two sheets or strips of paper with a layer of dough between. The paper may be an ordinary chipboard rather heavily s zed so that it will be water-resistant and tough, although, of course, other kinds of paper and facings may be used. The green sheet is then slid between two steam heated iron platens spaced a distance equal to the thickness desired for the finished board, say, for

instance, ,The steam platensmaynbe' heated with steam at a pressure of about 25 to 100 pounds. The application of heat of about that temperature causes the doughto pufi' up and force the upper sheet of paper or other facing against the upper platen. During this heating process water is driven off from the mixture, particularly along the edges of the board. In about thirty minutes the dough has puffed sufficiently and suflicient moisture has been driven off so thatthe board in its puffed and porous condition is rigid enough to be removed from the platens.

The tenacity with which the composition sticks to the paper sheets is one of the important characteristics of the paper faced board, for there is no tendency for the sheets to blister or strip away from the mineral filler. Th'epaper is very tenaciously held,

thereby strengthening the board and adding to its resistance against chipping during shipment, orv while nails are being driven through it. In cross section the inorganic.

facing of paper of a lesser thickness. Fora board weighing about 1200 pounds per 1000 square feet if a paper less than .037 inch in thickness is used for a facing material the surface of the boards will usually have small pockets or depressions which makes them unsaleable, except as seconds. The depressions also may. be in the form of waves. My novel method overcomes these difiiculties and it is possible to make wallboards with a fiat surface without pockets, depressions or waves.

Other objects and advantages of the present invention will become clear from the following description taken in conjunction with the accon'ipanying drawings, all of which are diagrammatic in character.

1 is a fragmentary section of a walledge of a board, bound withkraft paper and,

ready for trimming.

During the driven off from the doughlike mix. This steam comes from the water int-he silicate solution and it is the expansion of the water into steam that probably causes the cellular structure of the wallboard; While, no doubt ayery slight steam pressureis generated in the interior of the board due: to the friction of the cellular. passagesto the passage of the steam from the interior to the outside edges of the board, this pressure is not enough to prevent the formation of the ockets,de ressions andwaveswhich proba ly result rorn thedistortion of the paper due to the presence of unevenly distributed moisture and heat. By increasing the steam pressure on the interior surface of the facing it becomes a possible to force the facingagainst the platen and keep it fiat until the mix hardens and the paper or other facing material becomes thoroughly dried. The steam ressure must be great enoughtocounteract t e warping tendency of the pa er. Sincethesteam is generated during t e putnng action at the place where the pressure is needed it becomes necessaig to retainthe steamonthe interior of the pn ng and hardening wallboard. Several methods may be used. Figures 1 to 5 show different methods for maintaining thesteam pressure inside of the wallboardl cAll depend uponclosing theedges of the board to prevent the escapeof the steam. y

In Fig. 1 platens 1 are heated by steam,

oil or other media in the hollow spaces 2. The wallboard consists of the mix 5 with the adhering facings 4. The facings 4 project beyond the mix 5 and extend beyond the platens as shown." When the green board is in place the metal strip 3 with chamfered edgesmoves forward bet-ween theupper and lower projectin facings 4, forcing them against-the chain ered corners of the platens 1 and effectivel sealinthe edges of the board. The other e ges of t e board are similarly sealed.

When theheat from the platens evaporates the water in the mix andpufl's it, pressure is generated inside of the board, forcing the facings against the plane surfaces of the platens, and preventing wrinkles and pockets 4 from forming. The excess steam may be re lieved from the board interior at anytime by slightly loosening the steel strips Fig. 2 illustrates a modified 'method by which a steel frame 3maybe used to maintain the steam pressure inside of the wallboard. A steel frame of suitable dimensions, usually top platen slightly. The steel disadvantage of being diflicult to handle due slightly smaller than the platens, is laid o'n the green board. The frame may be made of round or square steel rods or other suitathe u per and lower facings .4 touch and form a tig 1t seals, thus preventing the escape of steams The thickness of the resulting board pulfing operation, steam 1s 3 is determined by the dimensions of the rod which constitutes the frame, plus the thickness of thetwo facings. A inch board with .032 inch facingsrequires 21.1%; inch rod. The

steamin the board is relieved by raising the frame has the to itsflexibilit It is diflicult to place exactlyas desire on the green board between the platens.

Figs. 3 and 4 show my preferred method for developinga steam pressure in the inside board. In Fig. 3 the strip of steel of the wal 3 or other suitable metal is fastened to either so a the top or'bottom platen 1 and acts in the samefmanner as the" steel frame 30f F'gbQ. y

The steel strip may be inset and fastene screws'or by welding to the platen. An alternative is shownin Figure 4 where one-' half ofthe steel strip 3 is fastened to the top and bottom platens respectivel The last method has theadvantage thatt e amount of board trim tothe top ofthe shoulder 7 y is" smaller thanpwhen the single strip is used.

The steain ma'y be relieved by'raising the top platen slightl I 1 i The method steam pressure, when used with paper facings of .030 to.035 inch thickness, require trim- Ining about to'l inchfrom the edge of the board. The, thick papers result in a. longer 8' described formaintaining the shoulder than the thin papers due to the it greater flexibility .of the latter. The amount i i i of trim may be cut to a minimum by utilizing the flexibility kraft at the edges of the board shownin Fig.

5. This illustrates a board after pufling. A

of a thin tough paper such as.

strip of thin tough paper 6 is pasted on the 1 1 interior of the facings 4 so that the strip projects beyond theedgeof thefacing 'far enough to allow the steel strip or frame 3 inFigs.

2, 3 and 4, to press it u on the lower strip and retain the steam wit in the board. In-

stead of forming a long shoulder as in Figs.

2, 3 and 4,the steampressure results in a" square shoulderyas shown in Fig. 5. This results in a minimum amountof trimat and also reenforces the facing at the edge where additional strength may be, utilized, and

is especially adapted to'the maintaining of binds the edge of the board. This method y it becomes possible to develop designs in relief on the surface of the board. The paper, which becomes somewhat plastic when heated in the presence of the steam from the green mix, may be molded to some extent. If de signs replace the plane surface of the platen and a steam pressure is maintained inside of .the board, the design on the platens will be found to be in reversed relief on the surface of the board. The advantage of this feature is apparent to those skilled in the art, especi ally for the marking ofthe surface in imitaan intumescent plastic and a filler while confined between paper facings to puff and solidify the mixture and cause it to adhere to the facings, and closing the edges of the board during the heating operation to mamtain a steam pressure upon the inner surfaces of the liners during the pufiing'operation.

2. A method of making a linedwall board consisting essentially of heating a mixture of an intumescent binder and a filler while c9nfined between paper facings with the outer surfaces of the facings in contact with plane surfaces to putt and solidify the mixture and cause it to adhere to the facings and closing the edges of the board to maintain steam pressure on the-inner surfaces of the facings uring the putting operation.

3. A method of making a lined wall board consisting essentially of heating a mixture of an intumescent binder and a filler while conlined between paper facings with the outer surfaces of the faci'ngs in contact with plane surfaces to puff and solidify the mixture and -;cause it to adhere to the facings and temporarily sealing some of the edges of the board to develop a steam pressure upon the inner surfaces of the facings during the puffing operation. 7 v

4:. A method of making a lined wall board consisting essentially of heating a mixture of an intumescent binder and a filler while confined between paper facings with the outer surfaces of the facingsin contact with plane surfaces to puff and solidify the mixture and cause it to adhere to the facings and holding the upper and lower facings together during the putting operation to maintain steam pressure upon t e inner surfaces of the liners until the pulling operation is complete.

5. A method of making a lined wall board consisting essentially of heating a mixture of an intumescent binder and a'filler while confined between paper facings with the outer surfaces of the facings in contact with plane surfaces to puff and solidify the mixture and cause it to adhere to the facings, closing the edges of the board to maintain steam pressure on the inner surfaces of the facin s during the puffing operation and ultimate y trimming away excess material from the edges that have been thus closed.

6. A method of making a lined wall board consisting essentially of heating a mixture of an intumescent binder and a filler while confined between paper facings to putt and solidify the mixture and cause it to adhere to the facings, said facings being in contact with heated, flat platens, and holding together the upper and lower facings along their edges to develop such steam pressure u on the inner surfaces of the liners during t e putting operation as will hold the outer surface of each liner in close contact withits adjacent platen.

7. A method of making a lined wall board consisting essentially of placing a mixture of.

an intumescent plastic and a filler between paper facings and heating the same by placing it between fiat platens, securing a flexible paper strip along the edge of one liner and pressing said paper strip against the other liner to temporarily seal the edges of the board and develop such steam pressure upon the inner surfaces of the liners as will insure close contact between the outer surface of each liner and its adjacent platen.

8. A method of making a lined wall board having surface designs 1n relief consisting essentiall of placing a mixture of an intumescent inder and a filler between paper liners, placing the liners and mixture between hot platens having the desired designs shaped therein and temporarily sealing the edges of the board to develop and maintain such steam pressure in intumescing material as will force the liners into close contact with the platens and insure reproduction of the designs formedtherewith.

9. A method of makin av lined wall board having surface designs in relief consisting essential] of placing a mixture of an intumescent inder and a filler between paper liners and placing the liners and filler between hot platens having the desired designs shaped OLIVER W. STOREY. 

